Created
November 21, 2022 17:45
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#include <bits/stdc++.h> | |
using namespace std; | |
const int MX = 1e5 + 5; | |
int t, n, a, b; | |
vector <pair<int, int> > adj[MX]; | |
void DFS(int par, int pos, vector <int> &v, bool flag){ | |
for(auto p : adj[pos]){ | |
int nxt = p.first; | |
int w = p.second; | |
if(flag && nxt == b) continue; | |
if(nxt == par) continue; | |
v[nxt] = v[pos] ^ w; | |
DFS(pos, nxt, v, flag); | |
} | |
} | |
int main(){ | |
cin.tie(nullptr), ios::sync_with_stdio(false); | |
cin >> t; | |
while(t--){ | |
cin >> n >> a >> b; | |
a--, b--; | |
for(int i = 1; i < n; i++){ | |
int u, v, w; | |
cin >> u >> v >> w; | |
u--, v--; | |
adj[u].emplace_back(v, w); | |
adj[v].emplace_back(u, w); | |
} | |
vector <int> v1(n, 0), v2(n, 0); | |
DFS(-1, a, v1, true), DFS(-1, b, v2, false); | |
v1[b] = -100, v2[b] = -1000; | |
sort(v2.begin(), v2.end()); | |
bool ans = false; | |
for(int i : v1){ | |
auto it = lower_bound(v2.begin(), v2.end(), i); | |
if(it != v2.end() && (*it) == i) ans = true; | |
} | |
for(int i = 0; i < n; i++) adj[i].clear(); | |
cout << (ans ? "YES\n" : "NO\n"); | |
} | |
} |
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